The formula of cyclopentane is C₅H₁₀
The structure and dot structure of cyclopentane is given below:

(i) Ethanoic acid:

 

(ii) Bromopentane:



(iii) Butanone:



(iv) Hexanal:



Structural isomers for bromopentane: There are three structural isomers for bromopentane depending on the position of Br at carbon 1, 2, 3. Position 4 and 5 are same as 1, 2.

(i) Bromoethane   

(ii) Methanal

(iii) 1, Hexyne

(i) You get a yellow, sooty flame if some of the holes in the bottom of burner are blocked and the burning does not get sufficient oxygen. 

ii) You get a blue flame if all the holes are open and sufficiently oxygen rich air is available.